The present invention relates to an electronic component, particularly to the electronic component which uses a piezo-electric resonator utilizing a balk wave propagating within a piezo-electric film.
A piezo-electric resonator capable of advantageously being made small in size is used in a duplexer for separating a transmission signal and a reception signal, for example, in a portable wireless communication apparatus.
In the duplexer using a conventional piezo-electric resonator, a transmission side filter and a reception side filter are fabricated into respective packages. The respective packages are contained in a package for an electric circuit substrate to form the duplexer. With this structure, the above-mentioned advantages of small size cannot be sufficiently obtained in the duplexer. As a result, the duplexer inevitably becomes large in size.
Under the circumstances, for the purpose of making the duplexer small in size, it can be considered that the piezo-electric resonator is mounted on a packaging substrate by a face-down bonding of a flip-chip using bumps (electrically connected projecting portion) in spite of a wire-bonding. By the flip-chip bonding, since a chip of the piezo-electric resonator can be electrically connected to the packaging substrate within an area of the chip, a two-dimensional space on the packaging substrate can be used efficiently. In addition, the duplexer can be made small in height, because the flip-chip bonding uses no wire that forms a loop and therefore needs a height to some extent.
Herein, a technique that the piezo-electric resonator is mounted on the packaging substrate by the flip-chip bonding is exemplified in, for example, Japanese laid open Official Gazettes No. 2002-232253, No. Hei 10-270979, respectively. Further, a technique that two piezo-electric resonators are mounted on the packaging substrate by the flip-chip bonding to form a duplexer is exemplified in, for example, Japanese laid open Official Gazettes No. Hei 11-88111, No. 2003-179518, respectively.
However, in the above-mentioned techniques, no description is made about shearing strength, particularly die shear strength.
The die shear strength is a value of a load obtained at the time when an IC (Integrated Circuit) chip (Herein, a piezo-electric resonator), that is mounted on a mounting substrate by a face-down bonding through electrically connected projecting portions (Herein, bumps), is pushed in a horizontal direction from the side thereof by the use of a shearing tool and thereby a junction portion between the IC chip and the mounting substrate or the IC chip itself is destroyed. If the die shear strength is not enough to a considerable extent, reliability against an impact is reduced.
In addition, the numbers or diameters of the bumps closely related to the die shear strength are different in respective piezo-electric resonators. It is therefore difficult to determine the value of the die shear strength enough to satisfy the above-mentioned reliability.